Cruisers Forum
 


Join CruisersForum Today

Reply
 
Thread Tools Rate Thread Display Modes
Old 12-05-2008, 13:50   #1
Registered User
 
c.spots's Avatar

Join Date: Jul 2007
Location: Now in Davao, the Philippines.
Boat: Leopard 40 catamaran
Posts: 121
Send a message via Skype™ to c.spots
high output alternator on 3YM30 Yanmar?

My engines are Yanmar 3YM30, 29 hp, with SD 20 saildrives. They have 80 aH alternators. I would like to have high output 115 aH alternators, but was informed that Yanmar does not recommend the high output alternator for this engine (but does for the smaller 19 hp engine,and indeed is a standard item for the boat with the smaller engine).

There seems to be plenty of space in the engine compartments. The battery bank is 3 X 180 aH AGM batteries.

Can somebody help me make sense out of why you shouldn't put a high output alternator on the larger engine (or any, for that matter)?
__________________

__________________
Robert W.
c.spots
www.changingspots.net

Life shouldn't be a race to the finish line - enjoy the journey.
c.spots is offline   Reply With Quote
Old 12-05-2008, 15:04   #2
Registered User

Join Date: Sep 2007
Location: Colombo
Posts: 1,059
I am not familiar with the engine but to start the ball rolling I suggest that a likely explanation is that the rating of the bearing on the pulley end of the crankshaft means it cannot reliably carry the bigger alternator's belt loads. This could be just because the bearing is "small" or the configuration of the engine means that there would be a big overhang away from the bearing to the added belt pulley.
__________________

__________________
MidLandOne is offline   Reply With Quote
Old 12-05-2008, 16:05   #3
Registered User

Join Date: Apr 2008
Location: Manchester Washington
Boat: Irwin- Barefoot 37CC (Custom MK V) "Quest"
Posts: 159
I have a Yanmar 3HM 35F which came with a 50 amp alternator and the same caution. The problem was the the bearing on the idler pulley which is the fresh water pump. The higher rated alternators require much higher torque to turn them so the drive belt has to be so tight that it overloads the fresh water pump pulley bearing

I put on a small frame 124 amp "Ample Power" alternator over their objections, and sure enough, I could not get the belt tight enough, and the belt spalled all over the engine compartment. I had a machine shop make up double pulleys and that has worked just fine for 13 or 14 years. I have not hurt the bearings or the water pump, or over tensioned the belts.

Good Luck

Joe S
__________________
svquest2 is offline   Reply With Quote
Old 12-05-2008, 18:20   #4
Moderator Emeritus
 
David M's Avatar

Cruisers Forum Supporter

Join Date: Sep 2007
Location: San Francisco Bay
Boat: research vessel
Posts: 10,150
Cummins uses a toothed belt that looks similar to a timing belt. Ask if that type of belt is an option for your engine. For obvious reasons, it can pull harder with less belt tension.

Also there are shops that can take an alternator and rebuild it with more output. I did that with my engines years ago. I went from a 105 amp alternator to a 160 amp alternator. The downside is I had to rev the engine up a bit to excite the field enough to get the amps I needed.

I would check Balmar's website or call them to see if they have any solutions.

David
__________________
David

Life begins where land ends.
David M is offline   Reply With Quote
Old 12-05-2008, 19:08   #5
Registered User
 
c.spots's Avatar

Join Date: Jul 2007
Location: Now in Davao, the Philippines.
Boat: Leopard 40 catamaran
Posts: 121
Send a message via Skype™ to c.spots
I can understand why a high output alternator could cause problems with an engine, but what really puzzles me is why it is ok for the smaller 19 hp, but not for the larger 29 hp 3YM30 engine. Could it even be true? Yanmar hasn't gotten back to me yet.
__________________
Robert W.
c.spots
www.changingspots.net

Life shouldn't be a race to the finish line - enjoy the journey.
c.spots is offline   Reply With Quote
Old 12-05-2008, 21:36   #6
Registered User
 
Strygaldwir's Avatar

Join Date: Dec 2004
Location: Deale, Maryland
Boat: SeaView - Privilege 37
Posts: 1,020
Images: 5
Robert:

Are you going to put new alternators on both engines? How do you balance the runtimes between the engines if you're only going to put them on one?

Are you sure you have 80 amps currently? I think mine are only 55 amps and they are the stock alternators that came with the engines.
__________________
Strygaldwir is offline   Reply With Quote
Old 12-05-2008, 22:55   #7
Registered User

Join Date: Apr 2008
Location: Manchester Washington
Boat: Irwin- Barefoot 37CC (Custom MK V) "Quest"
Posts: 159
Robert, difference could simply be the orientation of the alternator belts. The smaller engine may have a dedicated alternator belt where it has approximately 270% contact on each of two different pulleys (drive and alt), Your engine may be like mine, where the one belt goes over three pulleys, with only about 120% of contact on the alternator pulley. Thats why I couldn't tighten my belt tight enough; and it worked fine when I doubled the contact area by adding a second pulley.

Make sense?

Joe S
__________________
svquest2 is offline   Reply With Quote
Old 12-05-2008, 23:05   #8
Registered User
 
c.spots's Avatar

Join Date: Jul 2007
Location: Now in Davao, the Philippines.
Boat: Leopard 40 catamaran
Posts: 121
Send a message via Skype™ to c.spots
My amp meters were showing 70 to 75 amps max. The boat was supposed to already have an upgrade to high output 115 aH per the brochure specifications. When I checked the alternators, they were 80 aH. When I mentioned the discrepancy, I was informed that the 115 aH high output alternators were only for the basic 19 hp engines, not for the 29 hp upgrade engines, since it was not recommended by the manufacturer for the larger 3YM30 engine!
It doesn't make sense to me.
I think Yanmar has their own upgrade from 60 to 80 aH alternators.
__________________
Robert W.
c.spots
www.changingspots.net

Life shouldn't be a race to the finish line - enjoy the journey.
c.spots is offline   Reply With Quote
Old 13-05-2008, 00:19   #9
Senior Cruiser
 
Alan Wheeler's Avatar

Cruisers Forum Supporter

Join Date: Dec 2003
Location: Marlborough Sounds. New Zealand
Boat: Hartley Tahitian 45ft. Leisure Lady
Posts: 8,038
Images: 102
80A is at the top end of a single belt installation. Over 80A, you should be going to a double belt. Certainly a 115A Alt needs to have double belts. Either that, or a tooth or ribbed belt system, but that requires specialised pulleys on all areas.
Is there a chance that the small engine has a double belt system fitted?
__________________
Wheels

For God so loved the world..........He didn't send a committee.
Alan Wheeler is offline   Reply With Quote
Old 13-05-2008, 00:59   #10
CF Adviser
 
Pelagic's Avatar

Cruisers Forum Supporter

Join Date: Oct 2007
Boat: Van Helleman Schooner 65ft StarGazer
Posts: 6,872
I thought I would drive a large case 24v alternator off of my Northern Light 12Kw Generator. (Which is oversized for our live aboard use). My plan was to install a 240A @ 24V

I know Dick Gee from Northern Lights, (He is the VP and Engineering adviser for them) and I asked if they could make a custom PTO for this and mount it the way it should be.

He pretty much shot down that idea by saying:
“The problem is the tremendous side load imposed onto the nose of the engine crankshaft by the "V" belts when driving the alternator. We know from experience this can cause catastrophic failure. Based on this experience our 24v alternator limit is 40 Amps.

Also Nick, belt driven batter charging alternators are famously inefficient. On average they are 50% efficient. Have you considered a very large battery charger that could use the AC power from the generator OR shore power?"

So I think it probably can be done but the issue is that if not done right, you have major problems in the lower end, so the manufacturers are understandably conservative
__________________
Pelagic is online now   Reply With Quote
Old 01-04-2012, 14:38   #11
Registered User

Join Date: Mar 2012
Posts: 41
Re: high output alternator on 3YM30 Yanmar?

What were the cost of Yanmar 3YM30-SD marine saildrive engine 29 hp ?
__________________
white rabbitt is offline   Reply With Quote
Old 01-04-2012, 15:05   #12
Senior Cruiser
 
Cheechako's Avatar

Cruisers Forum Supporter

Join Date: Aug 2006
Location: Skagit City, WA
Posts: 19,342
Re: high output alternator on 3YM30 Yanmar?

It sounds like the smaller engine doesnt use an idler and the bigger one does...?
__________________
"I spent most of my money on Booze, Broads and Boats. The rest I wasted" - Elmore Leonard











Cheechako is online now   Reply With Quote
Old 01-04-2012, 15:23   #13
Registered User
 
SvLetitgo's Avatar

Join Date: Dec 2009
Boat: Lagoon 380 Letitgo
Posts: 110
Re: high output alternator on 3YM30 Yanmar?

Just did that install on this specific engine model. If you have any question don't hesitate

You can find the first post of the installation here

Electromaax install. · SV Letitgo

You will find more after

Good luck
__________________
svletitgo.com

From Dreamer to doer
SvLetitgo is offline   Reply With Quote
Old 01-04-2012, 15:53   #14
Ram
Registered User
 
Ram's Avatar

Cruisers Forum Supporter

Join Date: May 2005
Location: Cruising Greece
Boat: Cat in the med & Trawler in Florida
Posts: 2,298
Images: 27
Re: high output alternator on 3YM30 Yanmar?

i have a Balmar 125 amp single pully on my 3ym30 since 2006 works perfect with over 1300 hours on it- the smart external regulator went bad twice- likly due to my own fault
__________________

__________________
Ram is offline   Reply With Quote
Reply

Tags
3ym30, alternator, yanmar

Thread Tools
Display Modes Rate This Thread
Rate This Thread:

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Yanmar 3YM30 Oil Drain Location? ssullivan Engines and Propulsion Systems 40 10-11-2015 10:10
High Outpur Alternator vs Wind Generator Strygaldwir Electrical: Batteries, Generators & Solar 90 15-10-2011 12:02
Yanmar 3YM30 Overheating Talbot Engines and Propulsion Systems 9 25-02-2010 05:51
Comparable parts oil filters etc for Yanmar 3YM30 Pegasus SVYC Construction, Maintenance & Refit 0 24-03-2008 09:40
Bleeding the fue lines on a Yanmar 3YM30 chesapeakesailor Engines and Propulsion Systems 10 18-09-2006 06:55



Copyright 2002- Social Knowledge, LLC All Rights Reserved.

All times are GMT -7. The time now is 14:32.


Google+
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2017, vBulletin Solutions, Inc.
Social Knowledge Networks
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2017, vBulletin Solutions, Inc.

ShowCase vBulletin Plugins by Drive Thru Online, Inc.